Separation of As from high As-Sb dust using Fe2O3 as a fixative under O2-N2 atmosphere

Structural Destruction of As–Sb Solid Solution through a Selective Oxidation Process in the Presence of CaO and Its Effect on As Removal from the As–Sb Dust

“…For these reasons, it is difficult to separate As 2 O 3 from Sb 2 O 3 effectively via a roasting process under an inert atmosphere. As 2 O 3 and Sb 2 O 3 could be oxidized to nonvolatile compounds as shown in eqs 1–3; additionally, the Sb 2 O 3 oxidation is favored due to the more negative Gibbs free energy values of eqs 1 and 2 compared with that of eq 3(28) Thus, As 2 O 3 can be effectively separated from Sb 2 O 3 via a selective oxidation process, in which Sb is oxidized and transformed into nonvolatile Sb 2 O 4 and Sb 2 O 5 remaining in the residue, whereas As is volatilized in the form of As 4 O 6 (g). However, the oxidation of the “Sb 2 O 3 ” component in the (As, Sb) 2 O 3 solid solutions (eq 4) is hindered by the affinity between “As 2 O 3 ” and “Sb 2 O 3 ” in (As, Sb) 2 O 3 , seen from Figure 2.…”

“…A high As/Sb separation efficiency was realized in this process, and the As-containing volatiles could be collected and used for preparing FeAsO 4 , which renders the As harmless. 28 Meanwhile, the Sb in the roasted residue, which existed as Sb 2 O 4 , Sb 2 O 5 , Sb 6 O 13 , and Ca 2 Sb 2 O 7 , could be reclaimed through a general smelting process.…”

“…Based on the data shown in Figures and , when CaO was added, the oxidation of free Sb 2 O 3 and the “Sb 2 O 3 ” component in (As, Sb) 2 O 3 in the untreated dust is promoted, which also inhibits the formation of the As–Sb–O phase. Most of the Sb-containing phases were transformed to nonvolatile Sb 2 O 4 , Sb 2 O 5 , Sb 6 O 13 , and Ca 2 Sb 2 O 7 after roasting in the presence of CaO (Figure ), and massive volatilization of arsenic in the form of As 4 O 6 (g) was observed . Correspondingly, the arsenic and antimony volatilization rates increased to 92.69% and decreased to 6.77% (Figure ), respectively, when 5 mass % CaO was added.…”

Volatilized and Condensed Sb- and As-Bearing Phases Produced During Roasting of Cu-Rich Complex Concentrate in Nitrogen Atmosphere with Oxygen in Traces

“…The starting materials roasted in these studies were either pure compounds (As-and Sb-oxides and sulfides) [1][2][3][4] or dusts from non-ferrous pyrometallurgical processes, high in Sb and As contents. [5][6][7][8] These studies highlighted the attribute of vapor-phase complexation of volatile species of Sb and As leading to the formation of complex gaseous oxides, As n Sb 4Àn O 6 (g) and sulfides, As n Sb 4Àn S 6 (g), n = 1, 2, 3. Thermodynamic data for the vapor-phase complex oxides, As n Sb 4Àn O 6 (g) (n = 1, 2, 3), were determined by Li et al [1] These calculations were based on the exceptional property of zero heat of disproportionation reactions of these mixed oxide compounds [9,10] and the results of vapor transport experiments using As 2 O 3 (s) and Sb 2 O 3 (s).…”

“…[11] Equilibrium calculations based on these thermodynamic datasets supported the experimental findings that the formation of these complex species of As and Sb in the vapor-phase would facilitate an increased Sb-volatilization. [8,12] Sb and As form non-volatile oxide compounds at the oxidation potentials p O 2 >10 À10 bar and p O 2 >10 À5: 35 bar respectively. [13] Therefore, the volatilization of these elements from the sulfide concentrates during roasting have been studied in different controlled atmospheric environments.…”